WebMaster: Simone Zambenedetti
Laurea magistrale in Genetica e Biologia Molecolare nella Ricerca di Base e Biomedica
- Regolazione dell'espressione genica negli eucarioti (REGE I), Modulo I, 6 CFU
Laurea magistrale in Fisica:
- Biologia Molecolare, 6 CFU
Ricevimento: lunedì, martedì, giovedì ore 11,00-12,00
REGE I - martedì e giovedì ore 9.00-11.00 (I semestre)
Biologia Molecolare per Fisica - martedì e giovedì ore 14.00-16.00 (II semestre)
Mechanism and regulation of non coding RNA function in mammalian cells
1) The “RNA factory” and the biogenesis of non coding RNA.
It is now well accepted that starting from the very first step of gene expression, transcription initiation, the binding of specific factors tags the nascent ribonucleoprotein complexes such as to direct and convey them along specific pathways of maturation. These interactions can affect nuclear events such as mRNA maturation and processing as well as translation in the cytoplasm. We have described the existence of specific “RNA factories” also for other classes of polymerase II transcribed genes, such as those for non-coding RNAs (snoRNA and miRNA). In the past years we have studied the co-transcriptional recruitment of several factors required for the processing of primary transcripts and for the formation of the mature RNP particles. In the case of miRNAs we showed that Drosha is recruited during transcription and cleaves the pri-miRNA when still associated to the chromatin and that after Drosha cleavage, a torpedo-like mechanism acts on nascent long precursor miRNAs, whereby the Xrn2 exonuclease degrades the RNA polymeraseII-associated transcripts inducing its release from the template.
At present we are investigating the role of several Drosha-associated proteins (such as FUS/TLS and TDP-43) in controlling miRNA biogenesis.
2) Role of non coding RNA in gene expression control
Post-transcriptional control is a fundamental aspect of gene expression regulation. Many different processes have been described to control RNA maturation, stability and translation and many new functions have been assigned to RNA. Many of these processes require the participation of small non-coding RNA molecules that in most of the cases act as true regulators. An important function has been recently assigned to a family of microscopic RNAs (miRNAs) regulating mRNA and protein abundance. In our investigation of these mechanisms we have accomplished the characterization of several miRNA-dependent circuitries both in muscle, hematopoietic and neuronal differentiation.
Our current interest aims at exploiting and further developing the study of miRNA function and biogenesis in different types of syndromes, including neuronal and myeloid tumours and neuromuscular diseases. Moreover, we are testing whether manipulation of miRNA biosynthesis, or of their corresponding targets, can provide effective strategies for new therapeutic interventions.
long non coding RNA
One of the greatest surprises of high throughput transcriptome analysis of the last years has been the discovery that the mammalian genome is pervasively transcribed into many different complex families of RNA. In addition to a large number of alternative transcriptional start sites, termination and splicing patterns, a complex family of intronic, intergenic and antisense transcripts was found. Moreover, almost half of the polyadenylated species resulted to be non-protein-coding RNAs. Although many studies have helped understanding the function of many small non-coding RNAs, very little is known about the long non-coding (lncRNA) counterpart of the transcriptome.
A primary goal of our current research is to study the role of long non coding RNA in the control of normal muscle and neuronal differentiation and to identify their alteration occurring in neuromuscular and neurodegenerative diseases (Duchenne Muscular Dystrophy and Amyotrophic Lateral Sclerosis). The state of the art in this field is thoroughly advanced since well established master regulators (transcriptional factors and miRNA) have been deeply characterized and integrated in regulatory circuitries controlling muscle development and differentiation. However, recent discoveries point to the hierarchically relevant role of long non coding RNA (lncRNA), in the control of gene expression. Therefore, a major objective of this project is to re-evaluate and re-design established molecular circuitries known to control muscle differentiation in the light of the contribution of this class of RNA. In more general terms, this project will contribute to unravel the mechanisms by which non-coding RNAs contribute to cellular and organismal biology.
Both experimental and computational approaches are utilized to study the potential of these molecules to induce epigenetic effects or to act as antisense or decoys for RNA binding proteins and miRNA.
3) Therapeutic RNAs
Several different activities of RNA, such as decoy, ribozymes, and more recently antisense and RNAi, have been utilized in order to interfere with gene expression in a sequence-specific way. These methodologies were effectively employed as antiviral tools and as methods to modify transcript structure, such as the case of exon skipping. In the latter case we have provided a proof of principle for the therapeutic effectiveness of such molecular strategy for the cure of the Duchenne Muscular Dystrophy.
The use of the mdx mouse as the animal model for the Duchenne Muscular Dystrophy has allowed us to demonstrate the effectiveness of the antisense strategy in restoring the synthesis of dystrophin in vivo. In the last year we have been able to show that persistent exon-skipping and dystrophin rescue is maintained for the entire life of mdx mice through the use of Adeno-associated viral (AAV) expressing U1-antisense molecules. Therefore, this approach provides solid bases for the therapeutic treatment of DMD.